1. Field of the Invention
This invention relates to an electromagnet and an electromagnetic valve.
2. Description of the Prior Art
Conventionally, as small-sized coils in electromagnets, ones comprising bobbins having copper wires wound therearound are widely used. Other coils are also used which are produced by winding adhesive copper wires cylindrically and molding thus wound wires and heat-resisting synthetic resins into coils.
Since, in general, an attracting force of an electromagnet depends on ampere-turns thereof, while heat due to an increase in electric currents must be prevented from being caused, there arises such a problem that a large-sized coil must necessarily be prepared to provide the coil with a great attracting force.